MailBee.NET Address Validator

MailBee.NET Address Validator

Verify bulks of e-mail addresses
for correct syntax and existence
MailBee.NET Objects bundle includes SMTP, POP3, IMAP, EWS, Security, Antispam, Outlook Converter, Address Validator, PDF components and also BounceMail, HTML, MIME, ICalVCard components which are a free functionality.

MailBee.NET Address Validator is a high-performance, massively multi-threaded .NET component which can enable your applications to verify e-mail addresses for valid syntax, for domain name existence, DNS MX accuracy, and SMTP availability. It can deal with millions of addresses. Backed with commercial-grade support.

E-mail addresses to check can be taken from an array, DataTable, SQL Server, or from any other data source, including high-performance and memory conservative forward-only datasets. The available validation levels span from a simple regular expression check to making an SMTP connection and send attempt (without sending an actual message).

The component also supports complex multi-pass verification scenarios, such as when dealing with greylisting, temporary failures of target SMTP servers, and so on. A number of comprehensive samples and tutorials shipped with the product explain not only the basic usage of the component but advanced cases as well.

Visual Studio


Event-driven model lets the developer finely control the entire process, such as to implement dynamic blacklist or whitelist, track the operation progress in real time, or cancel it at any time.

The component fully supports the modern async/await API for building scalable and responsive applications.

MailBee.NET Address Validator can be used in any .NET language including C# and VB.NET. Supported .NET frameworks include .NET 2.0/3.0/3.5/4.0/4.5/4.6/4.7/4.8, both 32-bit and 64-bit.

MailBee.NET also supports .NET Core 1.0/2.0/3.0/3.1, .NET 5.0/.NET 8.0 and newer including ASP.NET Core and Xamarin, UWP (Universal Windows), Azure.

Top 100 publisher by ComponentSource

Over the years, MailBee.NET Objects has been among bestsellers on ComponentSource, the world's leading online shop of developer tools.

EmailAddressValidator object

  • Verify single address
  • Verify string array of addresses
  • Verify IDataReader or DataTable bulk of addresses
  • Check e-mail address syntax with a customizable regular expression
  • Perform DNX MX lookup (for better performance, multiple DNS servers can be used)
  • Make test SMTP connection to the destination SMTP MX server

EmailAddressValidator reference...

  • Send EHLO/'MAIL FROM'/'RCPT TO' commands to the server
  • Blacklists and whitelists via application-defined callbacks
  • UNIQUE In callbacks, the mechanism to access the data record the e-mail address currently being verified belongs to, even in multi-threaded mode and forward-only cursors (like SqlDataReader)
  • Comprehensive error checking, such as to distinguish between soft and hard failures, and to deal with greylisting
  • Extensive logging in file or memory
  • Can be extended with BounceMail component to refine detection of non-existing addresses with bounce handling

What's new

Version 12.4

  • .NET 8.0 officially supported

See Version History for details

Version 12.1

  • Separate UWP .NET Standard 2.0 edition for UWP apps targeting Windows 10 Fall Creators Update and newer. Has no Win32 dependencies and can be used in UWP Release builds published in Microsoft Store.
  • DNS MX query parser now supports large UDP responses (greater than 512 bytes).

Version 12.0

  • .NET Core 2.0 / .NET Standard 2.0 edition revised and improved, including better support of .NET Core 2.1 and 2.2.
  • .NET Standard 2.0 support in UWP. UWP apps targeting Windows 10 Fall Creators Update and newer can use the fully-functional .NET Standard 2.0 edition of MailBee.NET Objects.

Clients Say:

"I've been looking at the MailBee.NET application and love it." Matt Yeager
"Thanks again for your help. I like your products..." Ron Hill
"By the way I love your software. Great work thank you." Dennis Drogemuller